Comparison between the photo-excitation code and data for the Fe II^* column densities reported in Tables B.1, B.2, B.3, B.4, and B.5. We derive a GRB–absorber distance upper limit of 200 pc and 300 pc for Component I (purple) and II (black), respectively. For clarity reasons, the purple points have been slightly shifted to the right. Assuming that fine structures are produced by collisions instead of UV pumping, we derived a lower limit to the distance of d > 1700 pc for both components (model and column upper limit are in yellow).